DE19631939A1 - Digital ISDN video server - Google Patents

Description

The invention relates to a digital ISDN video server, which is a data stream provides encoded image and sound signals.

A distribution service for video telephones is known from ITU-T recommendation H.331. More specifically, the functionality for the distribution service (broadcast service) Are defined. In such a distribution service, the coding method is in the the picture and sound signals are coded. The are also specified Signaling parameters.

A so-called video phone server is also from the prior art known. This ISDN server offers a multitude of services to a caller. A caller calls the ISDN server via an ordinary ISDN H.320 videophone and can select information. Here are up to 1000 different Services offered. This videophone server provides 9 × 2 B channels.  

The function of storing the incoming information is also known. This saves a TV program that is currently being broadcast and can are sent with a time delay. Accordingly, a calling party can either do this beforehand query stored messages or messages transmitted in real time recall.

In a larger version of this videophone server, 15 × 2 channels can be used to be available. A disadvantage of such a server is that only 30 Video phones can access the server at the same time and that only Video telephones that work according to the H.320 video standard on this server Can get access (from: Interadive video telephony, from: company brochure of Telsis, Copyright, Telsis 1995, obtained on CeBit ′96).

It is an object of the present invention to provide a video server which is in the Is able to operate video phones of different designs. Another The object of the invention is to give a large number of subscribers access to the ISDN server to ensure.

This is achieved according to the invention by the teaching of patent claim 1.

It proves advantageous here that an inexpensive video server for video telephones different designs and configurations is created. Accordingly the video server can deliver data streams for any video phone and is thus universally applicable.  

Further advantageous refinements can be found in subclaims 2 to 9 remove.

A particular advantage here arises from claims 2 and 3, since additionally stored, coded picture and sound signals of different types Formats are provided, and thus a delayed retrieval of a Allow video message. This therefore includes both the function of a Video answering machine as well as that of a video recorder on a server.

Another advantage arises according to claim 4, which leads to a Fast forward and rewind within the encoded data stream is possible. This means that a passage can be viewed repeatedly or one Passage can be skipped by fast forwarding.

Advantageously, according to claim 5, this also means that Large number of participants can access a data stream.

An advantage in handling arises according to claim 6 by a Tone dialing from the video telephone is done to control the ISDN server to make. This can also be done via signaling in the B channel.

In the following the invention based on exemplary embodiments and Figures explained in more detail. The following figures show:

FIG. 1 Digital ISDN video server to provide data streams,

Fig. 2 Digital ISDN video server having a memory capacity for the information provided in real-time signals,

Figure 3 Schematic representation of a system using. An ISDN video server,

Fig. 4 representation of coded data streams for an interactive access.

The invention is explained in more detail below with reference to FIG. 1. A digital ISDN video server for the provision of data streams from coded image and sound signals CB1, CB2,. . ., CBm, CT1, CT2,. . ., CTn for video phones of different designs has a plurality of video coders VC1, VC2,. . ., VCm and a variety of audio coders AC1, AC2,. . ., ACn on. The video encoders and the audio encoders are used for real-time coding of uncoded picture or sound signals B, T. The large number of video encoders and the large number of audio coders serve to encoded picture and sound signals CB1, CB2,. . ., CBm, CT1, CT2,. . . To provide CTn.

The digital ISDN video server also assigns a switching unit V. Carrying out network signaling and establishing a connection between the video phones of different designs and the digital one ISDN video server. Calls make one through switch V. Video telephone via the ISDN network on the digital ISDN video server, which then become funds TN1,. . ., TNp for signaling a video telephone mediated. The switch V can be, for example, one that according to the I.400 series works. The means TN1,. . ., TNp for signaling one each Determine videophones  the coded video and audio signals that can be processed by the respective video telephones CB1, CB2,. . ., CBm, CT1, CT2,. . ., CTn. The funds TN1,. . ., TNp for Multiplexing or demultiplexing the coded picture and sound signals each for one Videophone and for performing error correction for each videophone. The terminal signaling can, for example, according to the H.242 ITU standard be performed. The multiplexer and demultiplexer can, for example, after the H.221 ITU standard, and the error correction can be done after H.261 ITU standard. Each agent TN1,. . ., TNp is for signaling connected to switch V.

Furthermore, the digital ISDN video server has a switching matrix AV-V for switching of the coded image and sound signals on the signaling means. This The switching matrix, which is used for audio / video distribution, is designed in such a way that the coded image signals CB1, CB2,. . ., CBm receives, as does the encoded audio signals CT1, CT2,. . ., CTn. The encoded picture and sound signals are like already explained above, available in different formats, which means that the picture and sound signals are coded differently and with a different Transfer rate can be transferred. The switching matrix AV-V switches the coded video and audio signals determined on the means according to the signaling TN1,. . ., TNp for signaling. Here, for example, the first means Signaling TN1 a first coded image signal CB1 and a second coded Sound signal CT2 switched on. On the second means of signaling TN2 is likewise the first coded picture signal CB1 and for example the first coded Sound signal CT1 switched on. Here is any constellation according to the processable image and sound signals possible.  

Furthermore, a controller S for control is in the digital ISDN video server the provision of the data stream. The control S is for example via a bus system BUS with any means TN1,. . . TNp connected for signaling, just as with the switching matrix AV-V and also with the multitude of Video coders VC1, VC2,. . ., VCm and with the multitude of audio coders AC1, AC2,. . ., ACn. Furthermore, the controller S is directly connected to the exchange V connected. After a video phone request to the digital ISDN video server arrives and on the funds TN1,. . ., TNp given for signaling has been used, the controller S serves to control the output of the coded picture and Control audio signals on the appropriate means for signaling. The Video encoder VC1, VC2,. . ., VCm can, for example, according to the H.261 ITU standard work. The audio encoders AC1, AC2,. . ., ACn work for example the G.711 or the G.722 standard. The according to the previous one Allow description of different formats for video telephones the selection of a signal quality suitable for a subscriber. So that is ensures that each participant has an optimal signal quality in his Device can have.

Is additionally carried out in the Fig. 1, an audio / video memory A / VS for providing stored, coded video and audio signals CB1 ', CB2'. . ., CBm ′, CT1 ′, CT2 ′,. . ., CTn. These stored, coded picture and sound signals are also in different formats, that is to say in different codings. For this purpose, the audio / video memory A / VS has a plurality of memories D1, D2. . ., Dk on. These memories can be designed, for example, in the form of disk memories. In addition to the audio and video signals encoded in real time, audio and video sequences from the memory are available in various formats. One embodiment of this is that the video and audio signals coded in real time are additionally stored on the audio and video memory A / VS. For this purpose, the coded video and audio signals present in real time at the switching matrix AV-V are routed to the audio / video memory in order to be stored there. It is therefore possible that incoming signals are recorded in real time and called up later. A possible use for image and sound signals stored in this way can be seen, for example, in the storage of messages. Current news, e.g. B. coming from television, are placed on the digital ISDN video server, stored there and can be accessed at any time from a videophone over an ISDN network. In the case of updated messages that arrive in the form of video and audio signals, this data can be overwritten, whereby a subscriber of a video phone has the option of querying updated messages at any time. In addition to pure video telephony, in which communication is carried out directly with another subscriber, this also results in an application that an image and audio message is recorded and called up later. This is the function of a so-called picture answering machine.

In the following it is explained with reference to FIG. 2 how image and sound signals present in real time are stored. An image signal B and a sound signal T are corresponding to the plurality of video coders VC1, VC2,. . ., VCm and on the large number of audio coders AC1, AC2,. . ., ACn on. The video encoders and the audio encoders are each shown combined, since an incoming image signal and an incoming audio signal can be encoded by each of the video encoders or by each of the audio encoders. The image signal B is encoded by one of the video encoders, which is why a coded image signal CB1, CB2,. . ., CBm is present. An incoming audio signal T is encoded by one of the audio encoders, which is why an encoded audio signal CT1, CT2,. . ., CTn is present. As already explained, these are placed on the switching matrix AV-V. If there is now a requirement that the coded picture and sound signals are stored, the coded picture signals CB1, CB2,. . ., CBm and the coded audio signals CT1, CT2,. . ., CTn given to the audio / video memory A / VS. There the incoming coded picture and sound signals are stored in memories D1, D2,. . ., Dk saved. This storage can be, for example, disk storage. The picture and sound signals stored in this way are now available to the switching network AV-V as coded, stored picture and sound signals CT1 ', CT2',. . ., CTn ′, CB1 ′, CB2 ′,. . ., CBm ′ are available. Thus, a user of the digital ISDN server has coded picture and sound signals and stored coded picture and sound signals available in real time.

To check what is currently being stored, the coded video and audio signals are sent to an audio / video decoder A / VD. Here it is stated, for example, that the coded picture signal CB2 and the coded sound signal CT2 are given to the audio / video decoder. This is thus decoded again into an image and sound signal B, T, and is considered for control. All elements of FIG. 2 are interconnected via a control. The controller S is connected to all elements via a bus BUS, for example, and controls the storage of the coded picture and sound signals.

A method for using the digital ISDN server is shown below with reference to FIG. 3. A first subscriber T1 on a video telephone Bife 1 dials a digital ISDN server SERV via an ISDN network ISDN. In the digital ISDN server SERV, according to the means explained above, it is determined which signals the video telephone set Bife 1 can process and accordingly a suitable signal quality is made available to it. An incoming picture and sound signal B, T can, as already explained, be processed or stored in real time and then transmitted to an image telephone. Another, second subscriber T2 is also connected to the digital ISDN server SERV via a Bife 2 video telephone. A third subscriber T3 is connected to the digital ISDN server SERV via a third video telephone device Bife 3 via the ISDN network ISDN. For the function of the so-called distribution service, the applied video and audio signals B, T are distributed to the three video telephones Bife 1 , Bife 2 , Bife 3 . It is possible that these three video telephones are of different designs. Different design means that these video telephones process different codes and process different transmission rates. The prerequisite here, as already explained in FIG. 1, was that signaling is carried out individually for each video telephone. This recognizes which coding and which data transmission a video telephone needs to have a high signal quality. Here, as shown in FIG. 3, the following coded image signals are made available by the digital ISDN server SERV, for example: CB1, CB3, CB1. The coded audio signals CT3, CT7, CT2 are also made available, for example. These are transmitted via the ISDN network, the video telephone set Bife 1 processing the coded image signals CB1 and the coded audio signal CT3. The video telephone set Bife 2 processes the encoded image signal CB3 and the encoded audio signal CT7. The video telephone set Bife 3 processes the signals CB1, CT2. The selection explained above is only an example.

In addition to the distribution service, so-called interactive control of the digital ISDN server is possible. An interactive control for a digital ISDN server is explained in more detail below with reference to FIG. 4. Shown in Fig. 4 is a coded video and audio signal, which is stored in multiple data streams DS1, DS2, DS3, DS4, DS5. So-called intra-frames are provided within the data streams DS1, DS2, DS3, DS4, DS5. Intra-frames contain a complete picture as picture content, whereas with the inter-sequences only the changes of the new picture in relation to the previous picture are transmitted. The individual data streams over time have, for example, in the data stream 1 DS1 a first intra frame at 0 seconds, a second intra frame at 30 seconds and a third intra frame at 60 seconds. In data stream 2 DS2, an intra-frame is shown after 5 seconds, a second intra-frame after 35 seconds. A first intra-frame after 10 seconds and a second intra-frame after 40 seconds are shown in data stream 3 DS3. A first intra frame after 15 seconds and a second intra frame after 45 seconds are shown in data stream 4 DS4. Accordingly, the data streams DS1 to DS4 differ in the placement of the intra-frames, ie the intra-coded pictures. So-called still images are present in the data stream 5 DS5. This means that intra-coded pictures are provided in quick succession in a timed form. However, intra-coded pictures with subsequent short inter-coded video sequences can also be provided. The positions of the intra-frames in the different data streams DS1 to DS4 and DS5 are stored in index files. The intra-frames allow the coded data stream to be placed at this point, since they contain a complete image content. Multiple access by individual participants to one of the data streams DS1 to DS4 also takes place at the location of the intra-frames, so that complete picture content is available. If the intra-sequence is set up, then you have to wait until the next intra-picture in order to have a complete picture content available again. As already explained, the data stream 5 DS5 is composed of intra-coded pictures and inter-coded sequences which follow one after the other. From the individual data streams DS1 to DS4, a branch is made to data stream 5 DS5. To implement the fast forward or rewind, the data stream 1 DS1 to the data stream 4 DS4 branches to the data stream 5 DS5 and winds in the corresponding direction. To continue running normally, data stream 5 DS5 is left again and jumped back to the matching data stream. Matching this means that a jump is made to the closest intra-frame or its data stream.

This is explained in more detail below using an exemplary embodiment and FIG. 4. The individual data streams DS1 to DS5 are arranged as previously explained. A subscriber now wishes, for example, to fast forward VSP in the data stream. For this purpose, the data stream 5 DS5 is branched from the data stream in which it is currently located. For example, data stream 2 DS2 branches to data stream 5 DS5 at time t = 13 seconds, that is, to the next intra-frame. Now fast-forward and stop, for example, at the time t = 42 seconds. From here the data stream should be queried further. The next intra-frame in terms of time is 45 seconds in the fourth data stream DS4.

Rewinding is done in a similar manner and is by drawing RSP indicated.

For this purpose, one of the data streams DS1 becomes any time exited to DS4, jumped to the data stream DS5 and rewound. After rewinding, one of the data streams DS1 to DS4 jumped back to the data stream whose intra-frame the jump back position follows next. Fast forward and rewind within a data stream is signaled by the Video telephone initialized. This can be done, for example, using tone dialing, more specifically, DTMF tone dialing (dual-tone multi-frequency). As another Design can be provided to provide this in the ISDN data stream.

Claims (8)

1. Digital ISDN video server, for the provision of data streams from coded video and audio signals (CB1, CB2,..., CBm, CT1, CT2,..., CTn) for video telephones of different designs,
with a large number of video coders (VC1, VC2, VCm) and with a large number of audio coders (AC1, AC2, ACn) for real-time coding of uncoded picture or sound signals (B, T) to provide the coded picture and sound signals (CB1, CB2,..., CBm, CT1, CT2,..., CTn) in different formats
with a switching unit (V) for carrying out a network signaling and for establishing a connection between the video telephones of different designs and the digital ISDN video server,
with means (TN1, TNp) for signaling a video telephone in each case for determining the coded video and audio signals (CB1, CB2,..., CBm, CT1, CT2,..., CTn) that can be processed by the respective video telephones and for multiplexing or Demultiplexing the coded video and audio signals each for a video phone and for performing error correction for each video phone,
with a switching matrix (AV-V) for switching the coded video and audio signals (CB1, CB2,..., CBm, CT1, CT2,..., CTn) to the signaling means (TN1, TNp)
and with a controller (S) for controlling the provision of the data stream from the digital ISDN video server for the video telephones of different designs via the means (TN1,..., TNp) for signaling. 2. Digital ISDN video server according to claim 1, with an audio / video memory (A / V-S) for the provision of stored, coded picture and sound signals (CB1 ′, CB2 ′,..., CBm ′, CT1 ′, CT2 ′,..., CTn ′) of different formats. 3. Digital ISDN video server according to claim 2, wherein the of the plurality of Video coders (VC1, VC2, VCm) and the large number of audio coders (AC1, AC2, ACn) signals provided in real time (CB1, CB2,..., CBm, CT1, CT2,..., CTn) in the audio / video memory (A / V-S) get saved.   4. Digital ISDN video server according to claim 2 or 3, wherein the control as Interactive control is formed, in each of which the coded picture and Sound signals (CB1, CB2,..., CBm, CT1, CT2,..., CTn) in several data streams (DS1, DS2, DS3, DS4, DS5) are stored and in which in each of the data streams (DS1, DS2, DS3, DS4, DS5) differently placed intra-frames to restart the Coding are arranged to perform the function of fast forwarding and Rewind within the encoded data stream. 5. Digital ISDN server according to claim 4, in which a multiple access individual Participants on a data stream over the intra-frames is made possible. 6. Digital ISDN server according to one of claims 1 to 5, in which one Data stream selection and control via tone dialing or signaling in the B channel. 7. Use of the digital ISDN server according to one of the preceding Claims for the realization of a distribution service. 8. Use of the digital ISDN server according to one of the preceding Requirements for the implementation of an interactive service.